I have 4 ohm bass driver which my amp disapproves of. I was planing to use 2 x 2 ohm resistors in series on the positive side to increase the resistance to 8 ohms (2+2+4). However, if I place the resistors 0ne on each of the speaker terminals (2+4+2) will it make any difference?
You realise you are going to burn the same amount of power in the resistors, as in the speaker? And that your damping factor will be terrible?
Sorry, but most commercial amps can handle 4 ohm loads. You could possibly look for a second hand amp if the budget is tight. When you put an inductor in series with the bass driver, that will also add to the resistance that the amp sees.
A different amp is not the way I want to go. I'm trying to do thins from free spare parts. I've put a used plate amp into a different cabinet. At higher volumes the sub pops and grunts. I actually want to increase the resistance the amp sees. The resistor seems to be the only real solution other than the crazy solution of using an additional driver purely for its inductive qualities. I'm going to go with a single 2ohm resistor - see if the amp can live with 6 ohms.
It might seem like the impedance matters, but all is not what it seems. The thing is, the speaker won't get as loud unless the amp supplies the same amount of current to it. It doesn't change whether you've added resistance or not. All that happens when you add resistance is you double the power when the speaker is the same loudness.
Therefore you just need to know the limit.
Therefore you just need to know the limit.
Well, adding resistors in series with the bass driver is not a good idea. Its better to either change bass driver to an 8 ohm driver or to use an inductor in series with the driver in the crossover that increases the impdance somewhat.
Popping and grunting, hmmm, sounds like a driver trying to go beyond Xmech (maximum excursion limit before damage). Not like an amp that runs out of current. Those mostly either switch off, burn fuses or destroy transistors... but about always that is quite a silent process.
You could try to lay your hands on some 250V-120V transformer of -say- about 200VA. Often used by people who move to or from the USA. Connect the 250V side to the amp and the 120V side to the woofer.
The transformer seems a good idea. Would it work also to scavenge an output transformer from an old (perhaps broken) tube amplifier and drive the 8 ohm tap and connect the speaker to the 4 ohm tap, using it as an autotransformer? This will of course reduce the voltage across the speaker but only by 3db while a series 4 ohm resistor in series will cause a 6dB drop (assuming that the speaker looks like a 4 ohm load). The damping factor will not be the same as with a direct connection, so it may sound different - perhaps a little better, perhaps a little worse. The power rating of the tube amp will help indicate if the transformer core is big enough for the power you have. Be sure to keep the other connections to the transformer insulated.
Adding 4 ohm in series with a 4 ohm speaker is a TERRIBLE idea on so many fronts.
Be aware that your "solution" will make your speaker receive one fourth of what it did before.
Were you aware of that?
That sounds like a POORLY deigned cabinet which does not load the speaker properly or the amp is underpowered (or you want way too much out of it).
Be aware that your "solution" will make your speaker receive one fourth of what it did before.
Were you aware of that?
Would a " site " transformer ( those heavy yellow lumps on building sites ) work? Although it does sound more like a voice coil bottoming out in the OPs discription. I have used a 1 ohm resistor ( with a 1 uf cap across it ) to lower the damping factor, and used a 4 ohm sub in series with a 4 ohm full range.
I thought I was batsh*t crazy but some of you guys are really out there! To answer an earlier question: the DC resistance is 3.2 Ohms. Some people are getting way ahead of themselves. I'm guessing the amp delivers about 15w RMS into 8 ohms - I'm not about to acquire a 200VA transformer from a building site!
I suspect a single 2 ohm 10w resistor will work just fine.
However, before I close up I am encouraged to try the crazy thing. I have 4" bass drivers coming out of my a$$. I'll try fixing one directly to the baffle purely to exploit its inductive properties.
I suspect a single 2 ohm 10w resistor will work just fine.
However, before I close up I am encouraged to try the crazy thing. I have 4" bass drivers coming out of my a$$. I'll try fixing one directly to the baffle purely to exploit its inductive properties.
Sorry, physics and reality check:
No, many can't, epically AVRs. Can you get away with them at moderate levels? Probably.
An inductor may add .3 or .4 Ohms and cost a bunch of money. It will do nothing for low frequency where the current is the problem.
6 Ohms is usually OK unless you push it. A used amp of higher quality is the best solution. I don't know what is is with all these 4 Ohm speakers when low end receivers and AVR's cant drive them. Pretty stupid to me. It is not just current, it can also be stability. So, stupid speakers and cheap amplifiers. Bad mix.
high watt resistors cost money, so depending on your woofer it may be sensible to just buy another one and connect in series, resulting in total 8 ohms with improved power handling and no wasted energy.
"Attitude" won´t solve your problem and people will avoid answering.
Biting helper´s hand means the stray street doggie won´t be fed any more.
But he said it's a plate amp, not an AVR.
A used one at that so it might even be faulty.
Don't you love posters who drip feed information.